Given the scarcity of allocated radio frequency spectrum, providers of air-to-ground (ATG) communication systems may make secondary use of already allocated spectrum, for example in the 14 gigahertz (GHz) range or use unlicensed bands, for example in the 2.4 GHz range, while providing ATG services. Unfortunately, radio frequency (RF) spectrum surveys show that RF noise and interference sources have risen over time, and are expected to continue to rise in the future. Some example surveys of the 2.4 GHz band observed noise rise on the order of 30 dB over a short period of time. Noise surveys also show a non-uniform distribution of noise levels over time or space. Such high levels of interference have the ability to significantly degrade the quality and available data bandwidth of the radio link, particularly if the objective is to provide consistent and reliable data rates that meet customer and industry expectations.
Given the presence of high RF noise and/or interference, at a given time, it is possible to find particular locations where noise or interference is low enough to guarantee an acceptable data rate. For example, for a given aircraft location, establishing a connection with acceptable data rate may utilize a scheme that selects the serving cell considering the noise levels from multiple candidate serving cell locations.
Network operators may establish primary communications for control information with the aircraft using their existing equipment and allocated spectrum and use the noisy 2.4 GHz spectrum primarily for data traffic. Primary in-flight communication networks may require reliable connectivity between ground and the aircraft, whereas supplementary in-flight communication networks may operate over noisy radio frequency spectrum. Some examples of primary networks may include satellite networks or other ATG networks that operate over licensed spectrum.
Schemes to select among ATG serving cells that maximize throughput to a given aircraft in the forward and return directions in a high interference frequency band may provide significant performance advantages in terms of stability of connection, available bandwidth, and latency.